Sökning: "sparse models"

Visar resultat 1 - 5 av 135 avhandlingar innehållade orden sparse models.

1. 1. Model Selection and Sparse Modeling

   Författare :Yngve Selén; Peter Stoica; Jean-Jacques Fuchs; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; model selection; model order selection; model averaging; nested models; sparse models; Bayesian inference; MMSE estimation; MAP estimation; ML estimation; AIC; BIC; GIC; RAKE receivers; pulse compression; radar; linear models; linear regression models; Signal processing; Signalbehandling;

   Sammanfattning : Parametric signal models are used in a multitude of signal processing applications. This thesis deals with signals for which there are many candidate models, and it is not a priori known which model is the most appropriate one. LÄS MER

3. 2. Estimation and optimal input design in sparse models

   Författare :Javad Parsa; Håkan Hjalmarsson; Kim Batselier; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; System identification; Sparse estimation; Input design; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Sparse parameter estimation is an important aspect of system identification, as it allows for reducing the order of a model, and also some models in system identification inherently exhibit sparsity in their parameters. The accuracy of the estimated sparse model depends directly on the performance of the sparse estimation methods. LÄS MER

4. 3. Classification models for high-dimensional data with sparsity patterns

   Författare :Annika Tillander; Tatjana Pavlenko; Daniel Thorburn; Patrik Ryden; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; High-dimensionality; supervised classification; classification accuracy; sparse; block-diagonal covariance structure; graphical Lasso; separation strength; discretization; Statistics; statistik;

   Sammanfattning : Today's high-throughput data collection devices, e.g. spectrometers and gene chips, create information in abundance. However, this poses serious statistical challenges, as the number of features is usually much larger than the number of observed units. LÄS MER

5. 4. Sparse Modeling Heuristics for Parameter Estimation - Applications in Statistical Signal Processing

   Författare :Stefan Ingi Adalbjörnsson; Matematisk statistik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; parameter estimation; sparse models; convex optimization; fundamental frequency; inharmonicity; audio localization; symbolic periodicity; alternating directions method of multipliers; N-dimensional decaying sinusoids.;

   Sammanfattning : This thesis examines sparse statistical modeling on a range of applications in audio modeling, audio localizations, DNA sequencing, and spectroscopy. In the examined cases, the resulting estimation problems are computationally cumbersome, both as one often suffers from a lack of model order knowledge for this form of problems, but also due to the high dimensionality of the parameter spaces, which typically also yield optimization problems with numerous local minima. LÄS MER

7. 5. Enhanced block sparse signal recovery and bayesian hierarchical models with applications

   Författare :Jianfeng Wang; Jun Yu; Anders Garpebring; Jia Li; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetic resonance imaging; Bayesian hierarchical models; Weather Research and Forecasting; Compressive sensing; Block sparsity; Multivariate isotropic symmetric a-stable distribution; q-ratio block constrained minimal singular value;

   Sammanfattning : This thesis is carried out within two projects ‘Statistical modelling and intelligentdata sampling in Magnetic resonance imaging (MRI) and positron-emission tomography(PET) measurements for cancer therapy assessment’ and ‘WindCoE -Nordic Wind Energy Center’ during my PhD study. It mainly focuses on applicationsof Bayesian hierarchical models (BHMs) and theoretical developments ofcompressive sensing (CS). LÄS MER